On Wed, Jun 06, 2018 at 11:17:36AM -0700, Samudrala, Sridhar wrote: > On 6/4/2018 7:06 PM, Jason Wang wrote: > > > > > > On 2018年06月05日 09:41, Samudrala, Sridhar wrote: > > > Ping on this patch now that the kernel patches are accepted into > > > davem's net-next tree. > > > https://patchwork.ozlabs.org/cover/920005/ > > > > > > > > > On 5/7/2018 4:09 PM, Sridhar Samudrala wrote: > > > > This feature bit can be used by hypervisor to indicate > > > > virtio_net device to > > > > act as a standby for another device with the same MAC address. > > > > > > > > I tested this with a small change to the patch to mark the > > > > STANDBY feature 'true' > > > > by default as i am using libvirt to start the VMs. > > > > Is there a way to pass the newly added feature bit 'standby' to > > > > qemu via libvirt > > > > XML file? > > > > > > > > Maybe you can try qemu command line passthrough: > > > > https://libvirt.org/drvqemu.html#qemucommand > > It looks like this can be used to pass command line arguments to qemu. > Is it possible to specify a virtio specific attribute via this method? > > For ex: to say mrg_rxbuf is off we can add the following line to virtio > section of the domain xml file. > <host mrg_rxbuf='off'/> > > I think libvirt needs to be extended to to support the new 'standby' attribute > via this mechanism. > Adding Liane Stump and libvirt to the CC list. > > Michael, > Can we start with getting this patch into Qemu and an update to libvirt to > support the 'standby' feature so that this feature can be enabled via > some scripts/orchestration layer for now. Unfortunately we don't give the hypothetical orchestration layer enough info about driver being bound, so it does not know when is it safe to add a primary. And a similar issue around reset. We could add events for that which would be a small patch, but the issue then is that guest can trigger a storm of these events. > We could improve this solution by enhancing Qemu to do automatic management of the > addition/deletion of the primary device based on feature negotiation as a later patch. I'm not sure what the point of the back and forth would be though. Typically after people invest in a specific config and get it working, it's very hard to move them to another solution. > > > > > The patch looks good to me. Let's see if Michael have any comment. > > > > Thanks > > > > > > Signed-off-by: Sridhar Samudrala <sridhar.samudrala@xxxxxxxxx> > > > > --- > > > > hw/net/virtio-net.c | 2 ++ > > > > include/standard-headers/linux/virtio_net.h | 3 +++ > > > > 2 files changed, 5 insertions(+) > > > > > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > > index 90502fca7c..38b3140670 100644 > > > > --- a/hw/net/virtio-net.c > > > > +++ b/hw/net/virtio-net.c > > > > @@ -2198,6 +2198,8 @@ static Property virtio_net_properties[] = { > > > > true), > > > > DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, > > > > SPEED_UNKNOWN), > > > > DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str), > > > > + DEFINE_PROP_BIT64("standby", VirtIONet, host_features, > > > > VIRTIO_NET_F_STANDBY, > > > > + false), > > > > DEFINE_PROP_END_OF_LIST(), > > > > }; > > > > diff --git a/include/standard-headers/linux/virtio_net.h > > > > b/include/standard-headers/linux/virtio_net.h > > > > index e9f255ea3f..01ec09684c 100644 > > > > --- a/include/standard-headers/linux/virtio_net.h > > > > +++ b/include/standard-headers/linux/virtio_net.h > > > > @@ -57,6 +57,9 @@ > > > > * Steering */ > > > > #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */ > > > > +#define VIRTIO_NET_F_STANDBY 62 /* Act as standby for > > > > another device > > > > + * with the same MAC. > > > > + */ > > > > #define VIRTIO_NET_F_SPEED_DUPLEX 63 /* Device set > > > > linkspeed and duplex */ > > > > #ifndef VIRTIO_NET_NO_LEGACY > > > > > -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
